diff --git a/Userland/Libraries/LibWeb/CSS/CSSRuleList.cpp b/Userland/Libraries/LibWeb/CSS/CSSRuleList.cpp
index e9a62093384..11ea56e41a0 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSRuleList.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSRuleList.cpp
@@ -189,13 +189,18 @@ bool CSSRuleList::evaluate_media_queries(HTML::Window const& window)
                 any_media_queries_changed_match_state = true;
             break;
         }
+        case CSSRule::Type::Style: {
+            auto& style_rule = verify_cast<CSSStyleRule>(*rule);
+            if (style_rule.css_rules().evaluate_media_queries(window))
+                any_media_queries_changed_match_state = true;
+            break;
+        }
         case CSSRule::Type::FontFace:
         case CSSRule::Type::Keyframe:
         case CSSRule::Type::Keyframes:
         case CSSRule::Type::LayerStatement:
         case CSSRule::Type::Namespace:
         case CSSRule::Type::NestedDeclarations:
-        case CSSRule::Type::Style:
         case CSSRule::Type::Property:
             break;
         }
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/MediaParsing.cpp b/Userland/Libraries/LibWeb/CSS/Parser/MediaParsing.cpp
index c0a89286e4c..8492fba460f 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/MediaParsing.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/MediaParsing.cpp
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2018-2022, Andreas Kling <andreas@ladybird.org>
  * Copyright (c) 2020-2021, the SerenityOS developers.
- * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021-2024, Sam Atkins <sam@ladybird.org>
  * Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
  * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
  *
@@ -10,6 +10,7 @@
 
 #include <AK/Debug.h>
 #include <LibWeb/CSS/CSSMediaRule.h>
+#include <LibWeb/CSS/CSSNestedDeclarations.h>
 #include <LibWeb/CSS/CalculatedOr.h>
 #include <LibWeb/CSS/MediaList.h>
 #include <LibWeb/CSS/MediaQuery.h>
@@ -627,10 +628,21 @@ JS::GCPtr<CSSMediaRule> Parser::convert_to_media_rule(AtRule const& rule, Nested
     auto media_list = MediaList::create(m_context.realm(), move(media_query_list));
 
     JS::MarkedVector<CSSRule*> child_rules { m_context.realm().heap() };
-    rule.for_each_as_rule_list([&](auto& rule) {
-        if (auto child_rule = convert_to_rule(rule, nested))
-            child_rules.append(child_rule);
-    });
+    for (auto const& child : rule.child_rules_and_lists_of_declarations) {
+        child.visit(
+            [&](Rule const& rule) {
+                if (auto child_rule = convert_to_rule(rule, nested))
+                    child_rules.append(child_rule);
+            },
+            [&](Vector<Declaration> const& declarations) {
+                auto* declaration = convert_to_style_declaration(declarations);
+                if (!declaration) {
+                    dbgln_if(CSS_PARSER_DEBUG, "CSSParser: nested declarations invalid; discarding.");
+                    return;
+                }
+                child_rules.append(CSSNestedDeclarations::create(m_context.realm(), *declaration));
+            });
+    }
     auto rule_list = CSSRuleList::create(m_context.realm(), child_rules);
     return CSSMediaRule::create(m_context.realm(), media_list, rule_list);
 }
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp b/Userland/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp
index 18ba3a17c73..b36b13c2853 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp
@@ -278,10 +278,21 @@ JS::GCPtr<CSSRule> Parser::convert_to_layer_rule(AtRule const& rule, Nested nest
 
         // Then the rules
         JS::MarkedVector<CSSRule*> child_rules { m_context.realm().heap() };
-        rule.for_each_as_rule_list([&](auto& rule) {
-            if (auto child_rule = convert_to_rule(rule, nested))
-                child_rules.append(child_rule);
-        });
+        for (auto const& child : rule.child_rules_and_lists_of_declarations) {
+            child.visit(
+                [&](Rule const& rule) {
+                    if (auto child_rule = convert_to_rule(rule, nested))
+                        child_rules.append(child_rule);
+                },
+                [&](Vector<Declaration> const& declarations) {
+                    auto* declaration = convert_to_style_declaration(declarations);
+                    if (!declaration) {
+                        dbgln_if(CSS_PARSER_DEBUG, "CSSParser: nested declarations invalid; discarding.");
+                        return;
+                    }
+                    child_rules.append(CSSNestedDeclarations::create(m_context.realm(), *declaration));
+                });
+        }
         auto rule_list = CSSRuleList::create(m_context.realm(), child_rules);
         return CSSLayerBlockRule::create(m_context.realm(), layer_name, rule_list);
     }
@@ -489,10 +500,21 @@ JS::GCPtr<CSSSupportsRule> Parser::convert_to_supports_rule(AtRule const& rule,
     }
 
     JS::MarkedVector<CSSRule*> child_rules { m_context.realm().heap() };
-    rule.for_each_as_rule_list([&](auto& rule) {
-        if (auto child_rule = convert_to_rule(rule, nested))
-            child_rules.append(child_rule);
-    });
+    for (auto const& child : rule.child_rules_and_lists_of_declarations) {
+        child.visit(
+            [&](Rule const& rule) {
+                if (auto child_rule = convert_to_rule(rule, nested))
+                    child_rules.append(child_rule);
+            },
+            [&](Vector<Declaration> const& declarations) {
+                auto* declaration = convert_to_style_declaration(declarations);
+                if (!declaration) {
+                    dbgln_if(CSS_PARSER_DEBUG, "CSSParser: nested declarations invalid; discarding.");
+                    return;
+                }
+                child_rules.append(CSSNestedDeclarations::create(m_context.realm(), *declaration));
+            });
+    }
 
     auto rule_list = CSSRuleList::create(m_context.realm(), child_rules);
     return CSSSupportsRule::create(m_context.realm(), supports.release_nonnull(), rule_list);